Oil burner



T. H. SMQOT May '2, 1939.

OIL BURNER Fil'ed Dec. 20, 1935 3 Sheets-Sheet l I I-ll III III I'I T.H. SMOOT May 2, 1939 SSheeqs-Sheet? mum T. H. SMOOT May 2, 1939.

OIL BURNER Filed Dec. 20, 1935 s Sheets-Sheet 5 Patented May 2, 1939 UNlT ED: STATES PATENT OFFICE Theophilus H. Smoot, Baltimore, Md.Application December 20, 1935, Serial No. 55,469

4 Claims.

This invention relates to fluid fuel burners of the pressure-typewherein ,a jet of fluid fuel, such as oil, is ignited and mixed with astream of air issuing from the nozzle of the burner.

Heretofore in the art of pressure type oil burners and the like thecustomary practice has been to ignite the oil and mix it with airissuing from the nozzle end of a blast tube through which air isforcedunder the pressure of a fan, the fan being housed in a casing providedwith a shutter controlled opening through which air is admitted, thevolume of air being regulated by adjustment of the shutter means on theinlet side of the fan.

This prevalent practice of the prior art results in a lowered efficiencyas the air propulsion means works against a partial vacuum'on its inletside and which is created by closing movement of the air volumeregulating means.

An object of the present invention is to provide an air blast fluid fuelburner provided with. air volume control means located on the airdischarge side of the air pump.

Another object is to provide in a burner 01 such character means forobtaining uniform air pressure within the'air blast tube.

A further object is to provide in a burner of this character novel meansfor regulating andcontrolling the air flow.

Other objects will be apparent from the description, among these beingto provide novel structural details of assembly together with means forimparting directional movement to air within the blast tube whereby uponissuing from the nozzle the air is caused to expand uniformly under theaction of centrifugal force.

The present disclosure constitutes an exposition of a practicalstructural embodiment by which the invention is reduced to practice. Itis to be understood that the details as shown and described are capableof variation within any limits not inconsistent with the scope of theinvention as claimed.

In the drawings:

Figure l issubstantially a vertical longitudinal f section through aburner constructed in. itCGOl'd.

ance with the invention, and illustrating certain details of theinternal mechanism in elevation.

Figure 2 is a section taken on line 2 2 at Fig. 1..

Figure 3 is a section on the line 3-4 of Fig. 1. Figure 4 is a sectionon the line 4- 3- of Fig. l. Figure'5 is a section on the line 5--t'oiFig. 1. Figure 6 is a group perspective view illustrating assemblydetails of an control means.

element of the air volume cal body of the burner.

Figure '7 is a top plan view of the burner, on a I reduced scale.

Figure 8 is a side elevation of the burner with the oil pump removed.

In the illustrated embodiment the burner coinc,

prises a main body portion 9 consisting of a substantially cylindricalhollow casting provided at its rear end with a pair of integraloppositely extending'lateralsupport arms disposed in a common horizontalplane the outer .ends of the in support arms being operatively engagedwith elevation adjustment ,screws H in screw jacks i2 and which areoperated in the usual manner by adjustment nuts i3. At the forward endof the able air propulsion means, such as a turbine blade fan generallydesignated as at it having a hub portion it rigidly connected with arotatable shaft ii extending transversely through the fan housing anddriven by suitable power means, comprising in this embodiment anelectric motor iii suitably secured to the integral casting comprisingthe body portion 9 and the fan housing it. The fan housing M, at theside opposite to that on which the motor I8 is mounted, is provided withan air inlet hood 19 having a vertical open face or grill N that ispermanently open to permlt of unobstructed air entry to the fan and soproportioned that the fan receives on its inlet side not less thanthemaximum volume of air which the fan is capable of moving. The face 402t) or an appropriate part of the hood it provides a mounting for a fueloil pump 26 that is operatively connected with the shaft ll driven. fromthe motor is. It will be noted that with respect to the fan the motor l8and the oil pump 25 are balanced at opposite sides of the fan hous= ing,the three units being axially aligned. The motor, the fan and'the oilpump are thus located in transverse axial alignment abovethe cylindri- 0The fan housing has a vertical discharge 22 directly downwardly into therear end of the cylindrical bodyportion 9, the housing being rear.-wardly extended somewhat beneath the fan by a web 23 to provide a plenumchamber 24 of uni- 5;,

form internal diameter from its rear end to a conical valve seat 25formed in the forward end v of the chamber. As shown in Fig. 1 theconical seat 25 opens to a venturi 26 located forwardly thereof andbetween the seat 25 and the inner end of the venturi the wall of thebody portion is formed with a cylindrical bore 21 to provide arestricted cylindrical throat through which air passes from the plenumchamber to the venturi or relief chamber 25. I

At its forward end the cylindrical body portion 3 has suitably securedthereto an axial extension consisting of an air blast tube or barrel 28having a uniform internal diameter from end to end which is less thanthe internal diameter of the plenum chamberand which provides an axialcontinuation of the plenum chamber 2 8.

The barrel 23 is provided with, means for changing the direction of airflow through the barrel for the purpose of imparting a swirling motionto the air as it issues from the nozzle end of the barrel. In theillustrated embodiment this means consists of an air spiral comprising ahub 23 of a diameter less than the diameter of the barrel and carrying aseries of spirally directed vanes or blades 30 which extend between thehub and the inner wall of the barrel, contacting the inner wall of thebarrel through the entire extent of their outer edges. Slidable axiallyin close fitting engagement through the hub 23 is electrode mount 3|having an inwardly directed apex so constructed that no air may passexcept through the spaces between the spirally directed blades 30. Theair spiral is anchored in position within the barrel by means ofattaching elements 32.

The barrel 28 in conjunction with the plenum chamber of the body 9provides a cylindrical air discharge passage having a restricted throat27 the bore of which is cylindrical and is coaxial with the cylindricalbore of the plenum chamber and the barrel. In its rear wall the body isprovided with an assembly port covered by a detachable closure plate 33formed with a central hub 34 which provides a bearing for an axiallyelongated sleeve member 35 coaxial with and rotatably mounted upon anoil discharge pipe or conduit 36 which extends axially throughoutsubstantially the entire longitudinal extent of the air dischargepassage of the burner. At the rear end of the burner the oil dischargepipe 36 extends through the detachable closure 33 and connects with aconduit 31 that leads to the oil pump. At the forward portion of theburner the oil pipe 36 is supported by the apex portion of the holder3|, through which holder the pipe 35 passes in close fitting engagement.At'its forward end the oil pipe 36 is provided with a conventionaldischarge tip 31' through which the oil issues to be ignited byelectrodes 38 and 39 mounted in bushings 40 and 4| passed. in sealedengagement through the conical holder 3| through countersunk sockets 42and 43 provided therein for the purpose. The electrical leads for theelectrodes are carried through bushings 44 in the wall of the barrel andthe barrel isfurther provided with a port 45 closed by a detachablecover plate 46 through which access may be had to the electricalconnections within the air passage.

Atits forward or nozzle end the barrel 28 is,

ulated at the outlet end of the plenum chamber, being controlled byvalve means cooperable with the reduced throat 21 and seat 25 andadjustable axially of the discharge passage. In the disclosed embodimentsuch valve means comprises a hollow substantially obloid member 50having a semi-spherical rear end portion 5|, a cylindrical centralportion 52 the axialextent of which is equal to or greater than theaxial extent of the cylindrical throat 21, and a conical front endportion 53, the three portions being integral and merging into oneanother.

An important feature of this invention resides in the fact that themaximum external diameter of the movable valve 50, as defined by itscentral cylindrical portion 52, is appreciably less than the internaldiameter of the restricted cylindrical throat 21 whereby there is at alltimes a clearance between the valve and the throat so that the valvemember may be shifted axially for movement entirely through the throat.The valve member 50 is mounted for sliding movement axially along thepipe 36, being restrained against rotation thereon by a gib 54 by whichthe valve and pipe are keyed together. A lateral tip 55 provides a stopmeans on the gib which defines the limit of forward axial movement ofthe valve. this limit being the maximum closing extent of the valve. Therear end or semi-spherical portion 5! of the valve member has a hub 56for traveling threaded engagement over the externally threaded extent ofthe sleeve 35 so that as the sleeve 35 is rotated the valve is caused tomove either forwardly or rearwardly depending upon the direction ofrotation of the sleeve. This rotation of the sleeve is accomplished bymeans of a handle member 51 rigidly secured at the outer end of thesleeve where, it projects through the detachable closure plate 33. Abearing sleeve 58 rigidly attached to the operating sleeve 35 on theinner side of the hub 34 cooperates with the handle member 51 torestrain the operating sleeve against axial movement over the supportingpipe 36. The dotted line position of the valve 50 as shown in Fig. 1indicates the position assumed by the valve in maximum open position. Adetachable cap 59 secured on the rear face of the burner body protectsthe adjusting handle 51 against accidental manipulation and uponremoving the cap 59 and detaching the closure 33 the valve assembly maybe withdrawn axially through the assembly port, the diameter of the portbeing greater than the maximum diameter of the valve member.

As shown in Fig. 1, it will be noted that the plenum chamber and airdischarge barrel are located in perpendicular relationship with respecttothe line of air flow as discharged through the fan outlet 2!. pressurewithin the plenum chamber becomes a static pressure so that the air flowis constant and unaffected by directional current ordinarily impartedwhere there is direct fan discharge.

In the operation of the burner there is no regulation or control of airon the inlet side of the fan; the fan inlet being unrestricted andtherefore receiving the full rated capacity. The fan thus moves its fullrated volume of air into the plenum chamber building up a staticpressure therein and the air flow volume is controlled in the dischargepassage by means of the valve asdescribed. Due to the clearance providedat all times between the cylindrical portion'52 of the valve and thecylindrical throat 21 of the air passage it will be evident that therewill actuating member supported by said pipe and at all times, be astraight line airflow past and around the valve, securing uniformdelivery to the same time against the wall of the barrel sothat when itissues through the nozzle annulus 41 it is traveling with a swirlingmotion which causes an expansion and dispersion by the action ofcentrifugal force. In order to relieve any vacuum creation at the areaimmediately adjacent the oil tip 31' the deflector 49 has been providedwhich insures that suflicient air will be passed directly around thetipto preclude the formation of avacuum.

Theventuri 26 providesan expansion chamber relieving air constrictionimmediately beyond the valve and this relief insures that the air flowwill be directed along the periphery of the barrel 28'and not confinedto its axial center.

.By dispersing the air flow to travel along the' peripheral innersurface of the discharge barrel there is obtained a greater freedom'forair flow as it is not obstructed by the electrodes and' nozzle adjacentthe axial center of the discharge tube. i

Having described my invention what I claim is:

1. An oil burner having, in combination, fuel supply means, air supplymeans, an air blast tube connected to said air supply means, an oildischarge pipe extending axially through said tube and connected to thefuel supply means, said tube having a constricted throat, air controlvalve means carried bysaid pipe and movable axially thereon into andentirely through said throat, a valve actuating member carried by saidpipe and movable thereon to operate said valve means, and means at theend of the oil discharge pipe for spraying oil-into the air leaving saidair blast tube. 5

tube having a constricted throat, an air control valve carried by saidpipe and 'movable axially thereon, said valve being of a size to passentirely through said throat with a clearance therebetween in allpositions of the valve, a valve movable thereon to operate said valvefor adjust ment in and through said throat, said valve having a surfacepresented to the line of air flow of a shape to direct air passed.thereby to the periphery of the tube beyond the valve, and means at theend of the oil discharge pipe for spraying oil into the air leaving saidair blast tube; I

3, An oil burner having, in combination, fuel supply means, air supplymeans, an air blast tube connectedto said air supply means and having aconstricted throat including a cyilindrically bored passage, an oildischarge pipe extending axially through said tube and passage andconnected to said fuel supply means, an air control valve carried bysaid pipe and movable thereon into and entirely through said throatpassage,

a valve actuating member supported by said:

pipe and movable thereon to operate said valve .for adjustment in andthrough said throat passage, said valve having a substantiallysemispherical portion presented to the line of air flow,

a cylindrical portion extending therefrom, and a conically reducedportion therebeyond, the maximum diameter of saidvalve being appreciablyless than the diameter of said cylindrical throat passage, and means atthe end of the oil discharge pipe for spraying oil into the air leavingsaid air blast tube.

4. An oil burner having in combination, fuel supply means, air supplymeans, a hollow tubular air discharge member, a plenum chamber there-'in in communication at one end with the air supply means, a constrictedthroat in the other end of said member, anair expansion chamber beyondsaid throat, an oil discharge pipe supported at one end in and extendingthrough a wall of the plenum chamber axially through said throat andinto the air expansion chamber, a fixed support in said air expansionchamber for the other end portion of said oil discharge pipe, means onsaid supportto direct air in a helical path along the wall of saidexpansion chamber prior to discharge therefrom, an air volume controlvalve movable axially on said oil discharge pipe into and through saidthroat, valve actuating means carried by said pipe'and movable thereon.to operate said valve, fuel atomizing means on said oil discharge pipein the discharge end of said air expansion chamber, and means forigniting the atanized fuel.

THEOPHILUS H. SMOOT.

